Control valve trim

ABSTRACT

Provided is a control valve trim, including a plug having a plurality of sections arranged in series along a longitudinal axis, wherein each of the plurality of sections has a diameter that is greater than the diameter of the preceding section, and a plurality of slots in the surface of each of the plurality of sections, and a liner, wherein the plug is disposed internal to the liner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of U.S. Non-Provisionalpatent application Ser. No. 12/743,562, entitled “Control Valve Trim,”filed May 18, 2010, which is herein incorporated by reference in itsentirety, and which claims priority to and benefit of PCT PatentApplication No. PCT/US2008/084428, entitled “Control Valve Trim,” filedNov. 21, 2008, which is herein incorporated by reference in itsentirety, and which claims priority to and benefit of U.S. ProvisionalPatent Application No. 60/990,233, entitled “Control Valve Trim”, filedon Nov. 26, 2007, which is herein incorporated by reference in itsentirety.

FIELD OF THE INVENTION

This invention relates to fluid systems. More particularly, the presentinvention relates to a valve for use with various flow control systems.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present invention,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentinvention. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

In a variety of fluid (e.g., including gas) handing systems, the flow ofa fluid is controlled by a valve. In the production of oil and naturalgas, valves are employed to direct and regulate the flow of fluids(e.g., gas, water, and oil) in pipes, wells, pumps, vessels, andrefineries. Valves generally include an open position that enables fluidflow and a closed position that reduces or completely shuts-off thefluid flow. Valves are also employed to regulate (e.g., throttle) thepressure and flow rate of the fluid flowing through the valve. Forexample, the valve may be partially closed, or may include an occlusionthat obstructs the fluid flow. An obstruction may include a controlvalve trim that throttles the fluid flow. Throttling is particularlyuseful where fluid flow occurs at a high rate and/or pressure and it isdesirable to reduce the flow rate and/or pressure. Accordingly, valvesemploying throttling may be particularly well suited to direct fluidflow from oil and gas wells where the pressure of the fluids beingexpelled from the mineral reservoir may exceed 3,000 pounds per squareinch (psi), for instance.

Due to the high flow rates and high pressures, fluids passing through avalve or the control valve trim may experience cavitation, flashing, andmay generate an excessive amount of noise. Further, the abrasive natureof fluids may cause erosion and extensive wear on components, such asthe control valve trim. Cavitation, flashing, vibrations due to noise,and erosion can individually, or in combination, reduce the performanceof the valve and may even lead to failure of the valve.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features, aspects, and advantages of the present invention willbecome better understood when the following detailed description is readwith reference to the accompanying figures in which like charactersrepresent like parts throughout the figures, wherein:

FIG. 1 is a perspective cross-sectioned view of a valve having a controlvalve trim in accordance with embodiments of the present technique;

FIG. 2A is a perspective cross-sectioned view of an embodiment of thecontrol valve trim of FIG. 1;

FIG. 2B is a cross-sectioned view of the control valve trim of FIG. 2Ataken across line 2B-2B of FIG. 2A;

FIG. 3A is a perspective cross-sectioned view of an embodiment of aliner of the control valve trim of FIGS. 2A-2B;

FIG. 3B is a cross-sectioned view of the liner of FIG. 3A taken acrossline 3B-3B of FIG. 3A;

FIG. 3C is a cross-sectioned view of an alternate embodiment of theliner of FIG. 3A in accordance with embodiments of the presenttechnique;

FIG. 4A is a perspective view of an embodiment of a plug of the controlvalve trim of FIGS. 2A-2B;

FIG. 4B is perspective sectioned view of the plug of FIG. 4A without thesection indicated by lines 4B-4B in accordance with embodiments of thepresent technique;

FIG. 4C is a cross-sectioned view of the plug of FIG. 4A taken acrossline 4C-4C of FIG. 4A;

FIG. 4D is a cross-sectioned view of the plug of FIG. 4A taken acrossline 4D-4D of FIG. 4A;

FIG. 5A is a perspective view that illustrates an exemplary fluid flowpath in accordance with embodiments of the present technique;

FIG. 5B is a cross-sectioned view of the plug, the liner, and a flowpath, in accordance with embodiments of the present technique;

FIG. 5C is a cross-sectioned view of the plug and the liner thatillustrates two flow paths in accordance with embodiments of the presenttechnique;

FIGS. 6A and 6B are perspective views of another exemplary embodiment ofa plug of the control valve trim;

FIG. 7A is a perspective view of another exemplary embodiment of a linerof the control valve trim, for use with the plug of FIGS. 6A and 6B;

FIG. 7B is a cross-sectioned view of the exemplary liner embodiment ofFIG. 7A;

FIG. 8 is a cross-sectioned view of the control valve trim,incorporating the exemplary plug and liner embodiments of FIGS. 6 and 7;

FIGS. 9A and 9B are perspective views that illustrate exemplary fluidflow paths in accordance with embodiments of the present technique; and

FIG. 10 is a block diagram of a fluid system in accordance withembodiments of the present technique.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present invention will bedescribed below. These described embodiments are only exemplary of thepresent invention. Additionally, in an effort to provide a concisedescription of these exemplary embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

Referring now to FIG. 1, the illustrated valve system 10 includes avalve 12 having a control valve trim 14 in accordance with embodimentsof the present technique. Specifically, the control valve trim 14includes a multistage, rising stem and expanding area control valve trimconfigured for use in severe (e.g., high pressure and flow rate)service. In the illustrated embodiment, the control valve trim 14includes a plug 16 disposed in a liner 18. The control valve trim 14 isdisposed inside of a flow bore 20 of a valve body 22.

In operation, fluid flows into the flow bore 20 of the valve body 22 viaan inlet 24, through the control valve trim 14 and exits the valve 12via an outlet 26. (It will be appreciated that the term fluidencompasses fluid media including a liquid and/or gaseous state, such aswater and steam, and further encompasses mixed-phase media, such asmedia having suspended solids, for example.) As the fluid passes throughthe control valve trim 14, the fluid is directed through a variety ofthrottling (e.g., pressure and/or velocity reducing) points that absorbenergy from the fluid, thereby reducing the pressure and the velocity ofthe fluid as it travels through the control valve trim 14.

Flow characteristics of the passing fluid can be regulated or altered bymanipulating the position of the plug 16. The position of the plug 16relative to the liner 18 may be controlled via an actuator mechanism 28.The actuator mechanism 28 may be employed to slide the plug 16 along alongitudinal axis 30 of the bore 20 and the control valve trim 14. Forexample, in the illustrated embodiment, the actuator mechanism 28includes a stem disposed parallel to the longitudinal axis 30 andcoupled to the plug 16.

Turning the fluid from one direction to another may provide an effectivereduction of fluid velocity. However, the fluid acting on a surface,such as the plug 16 or liner 18, may cause a high rate of localizederosion. Increasing the bend radius may distribute the energy across alarger area, thereby reducing the likelihood of erosion. However,reducing the turn angle may include throttling over a large distance(e.g., sweep) making it impractical in the physical space limitations ofthe valve system 10.

A change in area along the fluid path may produce less trim surfaceerosion (e.g., wear), as suggested above, and may be capable ofabsorbing the same amount of energy due to the velocity and turbulenceof the fluid flow that is occurring a distance away from the surface.However, an expanding area may employ an increasing amount of space toabsorb a given amount of energy. Further, the pressure drop along theflow path may cause some fluids to expand, and can result in the processstream choking (e.g. being restricted) on subsequent stages. In otherwords, the fluid path may be inhibited by the low-pressure high-volumefluid down stream, resulting in a reduced throughput of the valve 12.

The embodiments discussed in further detail below include a system andmethod of throttling the fluid through the control valve trim 14 thatemploys horizontal and vertical fluid turns with increasing flow area.The control valve trim 14 includes multiple stages having an expandingarea between stages, in certain embodiments. For instance, the plug 16and liner 18 may each include expanding diameters between each of thestages. In certain embodiments, the control valve trim 14 may inhibitflashing (e.g., the pressure dropping to a level causing the fluid tobubble) of expanding fluids. Further, in certain embodiments, a diameterof a last stage may be larger than the diameter of the first stage. Theflow path through the control valve trim 14 may include axial, normal,and circumferential fluid flow. In other words, the control valve trim14 provides a three-dimensional (3D) tortuous fluid path ofinterconnected stages (e.g., chambers). Each flow turn of the fluid pathincludes an area increase to reduce the fluid velocity at the trimsurface, thereby helping to reduce the erosion at the trim surface.

The increase in flow area can also result in the valve 12 and thecontrol valve trim 14 being trash-tolerant. In other words, thesequential increase in size may help to reduce the likelihood of debrisforming a clog between the plug 16 and the liner 18.

Further, the larger diameter of the last stage of the control valve trim14 also facilitates the inclusion of a guide bushing with an integralbalance chamber, in certain embodiments. The chamber can be energizedvia a pressure tap to an upstream stage, and the amount of force can betailored to the application by changing the position of the pressuretap. In operation, as the fluid media pressure acts on the plug 16 fromthe upstream direction, the balance chamber can exert a force in theopposite direction to balance the force acting on the plug 16. Incertain embodiments, the balance chamber may be employed to provide abalancing force across the plug that facilitates reducing the size ofthe actuator mechanism 28. It is further noted that no direct contactseals may be employed in the balancing valve trim. Thus, the valvepressure, temperature, and/or chemistry may not be limited to commonseal materials.

Turning now to FIGS. 2A-2B, an embodiment of the control valve trim 14is depicted. As discussed previously, the control valve trim 14 includesthe plug 16 and the liner 18. The plug 16 and the liner 18 are disposedcoaxially along the longitudinal axis 30. In the illustrated embodiment,the control valve trim 14 includes a throttling channel 32. The channel32 includes a region between an exterior surface 34 of the plug 16 andan interior surface 36 of the liner 18. The channel 32 includes sixstages 40, 42, 44, 46, 48, and 50 that are defined by protrusions 52,54, 56, 58, 60, and 61 of the plug 16, and annular recesses 62, 64, 66,68, 70, and 71 of the liner 18, respectively. The stages 40, 42, 44, 46,48, and 50 are arranged in series, such that fluid may flow in from afirst end 74 of the channel 32, pass through each of the six stages 40,42, 44, 46, 48, and 50, and exit via a second end 76 of the channel 32.

FIGS. 3A-3B illustrate a perspective-sectioned view and a sectioned viewof the liner 18 in accordance with aspects of the present technique. Theliner 18 includes a liner body 80 having a first (upstream) end 82 and asecond (downstream) end 84. The first end 82 is configured to bedisposed in the flow bore 20 of the valve 12 and to direct fluid flowinto the channel 32 that is defined by the internal surface 36 of theliner 18. The second end 84 is configured to be disposed proximate theoutlet 26 of the valve 12. In the illustrated embodiment, the second end84 of the liner 18 includes recesses 86 (e.g., annular recesses) thatmay accept a sealing member (e.g., a metallic or elastomeric sealingring) disposed between the liner 18 and the valve 12, or between theliner 18 and another component, such as a pipe or flange, coupled to theoutlet 26 of the valve 12.

The liner 18 includes an external surface 88 that facilitates disposingthe liner 18 into the fluid bore 20 of the valve 12. In other words, theprofile of the external surface 88 is similar to and/or conforms to theprofile of an internal surface of the fluid bore 20. When the liner 18is disposed in the fluid bore 20, the interface between the liner 18 andthe fluid bore 20 may effectively create a seal, thereby forcing fluidfrom the bore 20 into the channel 32 of the control valve trim 14.

The internal surface 36 of the liner 18 is defined by the series ofannular recesses 62, 64, 66, 68, 70, and 71. In the illustratedembodiment, the liner 18 includes six of these annular recesses 62, 64,66, 68, 70, and 71. Each of the recesses 62, 64, 66, 68, 70, and 71includes a notch that sweeps about the interior 36 of the liner 18. Inthe illustrated embodiment, the annular recesses 62, 64, 66, 68, 70, and71 each include an internal face 90 that is approximately parallel withthe longitudinal axis 30. The faces 90 define internal radii 92, 94, 96,98, 100, and 102 of the annular recesses 62, 64, 66, 68, 70, and 71,respectively. In one embodiment, all or some of the faces 90 may beoriented at an angle to promote certain fluid flow paths. For example,as depicted in FIG. 3C, each of the faces 90 are oriented at an angle 91from the longitudinal axis 30.

Further, the annular recesses 62, 64, 66, 68, 70, and 71 may bedescribed as defining seven annular protrusions 104, 106, 108, 110, 112,114, and 116. The annular protrusions 104, 106, 108, 110, 112, 114, and116 each include a ring-like or rib-like structure between the annularrecesses 62, 64, 66, 68, 70, and 71 and between the first and secondends 82 and 84 of the liner 18. Each of the protrusions 104, 106, 108,110, 112, 114, and 116 includes an internal face 118 that isapproximately parallel with the longitudinal axis 30. Accordingly, thefaces 118 may be parallel with the faces 90 of the annular recesses 62,64, 66, 68, 70, and 71, discussed above. The faces 118 define internalradii 120, 122, 124, 126, 128, 130, and 132 of the protrusions 104, 106,108, 110, 112, 114, and 116, respectively. In other embodiments, all orsome of the faces 118 may be oriented at an angle to promote certainfluid flow paths.

As illustrated, the radius of each annular recess 62, 64, 66, 68, 70,and 71 may be equal to or greater than the radius of the preceding(e.g., upstream) annular recess. In one embodiment, the radius 102 ofthe last annular recess 71 is approximately twice (2×) the radius 92 ofthe first annular recess 62 of the liner 18. Similarly, each of theprotrusions 104, 106, 108, 110, 112, 114, and 116 may be equal to orgreater than the radius of the preceding (e.g., upstream) protrusion. Inone embodiment, the radius 132 of the last protrusion 116 (e.g., anoutlet 134 of the liner 18) is approximately twice (2×) the radius 120of the first protrusion 104 (e.g., an inlet 136) of the liner 18.

For example, in the illustrated embodiment, the first radius 92 isapproximately 1.4 inches, the second radius 94 is approximately 1.5inches, the third radius 96 is approximately 1.72 inches, the fourthradius 98 is approximately 1.88 inches, the fifth radius 100 isapproximately 2.11 inches, and the sixth radius 102 is approximately2.25 inches. Further, with regard to the protrusions 104, 106, 108, 110,112, 114, and 116, the first radius 120 is approximately 0.85 inches,the second radius 122 is approximately 1 inch, the third radius 124 isapproximately 1 inch, the fourth radius 126 is approximately 1.38inches, the fifth radius 128 is approximately 1.38, the sixth radius 130is approximately 1.75, and the seventh radius 132 is approximately 1.75inches.

FIGS. 4A-4D illustrate the plug 16 in accordance with embodiments of thepresent technique. As illustrated, the plug 16 includes a series ofcylindrical sections increasing in diameter from a first (upstream) end150 to a second (downstream) end 152 of the plug 16. In the illustratedembodiment, a first section (stem) 154 includes a cylindrical protrusionextending from the first end 150 of the plug 16. In certain embodiments,the stem 154 may be coupled to the actuator mechanism 28, as discussedabove with regard to FIG. 1. In the illustrated embodiment, the stem 154includes an outer diameter 156 that is equal to or less than thediameter of the inlet 136 of the liner 18. For example, in theillustrated embodiment, the diameter 156 of the stem 154 isapproximately 1.09 inches. The plug 16 may be inserted through theoutlet 134 of the liner 18 such that the stem 154 extends through theinlet 136.

A second section 160 of the plug 16 includes an outer diameter 162 thatis greater than the diameter 156 of the stem 154. Further, the outerdiameter 162 of the second section 160 is less than or equal to theinner diameter 122 of the second protrusion 106 and the inner diameter124 of the third protrusion 108 of the liner 18. For example, in theillustrated embodiment, the diameter 162 of the second section 160 isapproximately 2 inches.

Further, the second section 160 includes multiple slots that areconfigured to direct fluid flow around the plug 16. For example, a pairof first slots 164 is cut into the outer surface of the second section160 proximate the stem 154 (upstream). The slots 164 are on oppositesides of the second section 160 from one another (e.g., offset on eitherside of the longitudinal axis 30), and are aligned with one anotheralong a plane transverse to the longitudinal axis 30. In other words,the slots 164 are cut at approximately the same axial location along thelength of the plug 16. The slots 164 have faces 166 that are parallel toone another and parallel to the longitudinal axis 30. A lower face 168of each slot 164 is perpendicular to the face 166 and to thelongitudinal axis 30. An upper face 170 of each slot 164 is angledrelative to the face 166 and to the longitudinal axis 30. The anglebetween the upper face 170 and the face 166 is obtuse. In other words,the upper face 170 defines a chamfer that extends from the outer surfaceof the second section 160 to the face 166.

A pair of second slots 174 is cut into the outer surface of the secondsection 160 proximate a third section 176 (downstream). The slots 174are on opposite sides of the second section 160 from one another (e.g.,offset on either side of the longitudinal axis 30), and are aligned withone another along a plane transverse to the longitudinal axis 30. Inother words, the slots 174 are cut at approximately the same axiallocation along the length of the plug 16. The slots 174 have faces 178that are parallel to one another and parallel to the longitudinal axis30. However, the slots 174 are not parallel to the first slots 164. Theslots 174 are rotated 90 degrees about the longitudinal axis 30 suchthat the faces 178 of the slots 174 are oriented perpendicular to thefaces 166 of the first slots 164 (e.g., planes passing through the firstfaces 166 and the second faces 178 are parallel to the longitudinal axis30, and are perpendicular to one another). A lower face 180 of each slot174 is defined by a top surface of the third section 176 that isperpendicular to the face 178 and to the longitudinal axis 30. An upperface 182 of each slot 174 is angled relative to the face 178 and to thelongitudinal axis 30. The angle between the upper face 182 and the face178 is obtuse. In other words, the upper face 182 defines a chamfer thatextends from the outer surface of the second section 160 to the face178.

The third section 176 of the plug 16 includes an outer diameter 184 thatis greater than the outer diameter 162 of the second section 160.Further, the outer diameter 184 of the third section 176 is less than orequal to the inner diameter 126 of the fourth protrusion 110 and theinner diameter 128 of the fifth protrusion 112. For example, in theillustrated embodiment, the diameter 184 of the third section 176 isapproximately 2.75 inches.

Similar to the second section 160, the third section 176 includesmultiple slots that are configured to direct fluid flow around the plug16. For example, a pair of first slots 186 is cut into the outer surfaceof the third section 176 proximate the second section 160 (upstream).The slots 186 are on opposite sides of the third section 176 from oneanother (e.g., offset on either side of the longitudinal axis 30), andare aligned with one another along a plane transverse to thelongitudinal axis 30. In other words, the slots 186 are cut atapproximately the same axial location along the length of the plug 16.The slots 186 have faces 188 that are parallel to one another andparallel to the longitudinal axis 30. The faces 188 are also parallel tothe faces 166 of the first slots 164 in the first section 160. A lowerface 190 of each slot 186 is perpendicular to the face 188 and to thelongitudinal axis 30. An upper face 192 of each slot 186 is angledrelative to the face 188 and to the longitudinal axis 30. The anglebetween the upper face 192 and the face 188 is obtuse. In other words,the upper face 192 defines a chamfer that extends from the outer surfaceof the third section 176 to the face 188.

A pair of second slots 194 is cut into the outer surface of the thirdsection 176 proximate a fourth section 196 (downstream). The slots 194are on opposite sides of the third section 176 from one another (e.g.,offset on either side of the longitudinal axis 30), and are aligned withone another along a plane transverse to the longitudinal axis 30. Inother words, the slots 194 are cut at approximately the same axiallocation along the length of the plug 16. The slots 194 have faces 198that are parallel to one another and parallel to the longitudinal axis30. However, the slots 194 are not parallel to the first slots 186. Theslots 194 are rotated 90 degrees about the longitudinal axis 30 suchthat the faces 198 of the second slots 194 are oriented perpendicular tothe faces 188 of the first slots 186 (e.g., planes passing through thefirst faces 188 and the second faces 198 are parallel to thelongitudinal axis 30, and are perpendicular to one another). The faces198 are also parallel to the faces 178 of the second slots 174 in thefirst section 160. A lower face 200 of each slot 194 is defined by a topsurface of the fourth section 196 that is perpendicular to the face 198and to the longitudinal axis 30. An upper face 202 of each slot 194 isangled relative to the face 198 and to the longitudinal axis 30. Theangle between the upper face 202 and the face 198 is obtuse. In otherwords, the upper face 202 defines a chamfer that extends from the outersurface of the third section 176 to the face 198.

The fourth section 196 of the plug 16 includes an outer diameter 204that is greater than the outer diameter 184 of the third section 176.Further, the outer diameter 204 of the fourth section 196 is less thanor equal to the inner diameter 130 of the sixth protrusion 114 and theinner diameter 132 of the seventh protrusion 116. For example, in theillustrated embodiment, the diameter 204 of the fourth section 196 isapproximately 3.5 inches.

Similar to the second and third sections 160 and 176, the fourth section196 includes multiple slots that are configured to direct fluid flowaround the plug 16. For example, a pair of first slots 206 is cut intothe outer surface of the fourth section 196 proximate the third section176 (upstream). The slots 206 are on opposite sides of the fourthsection 196 from one another (e.g., offset on either side of thelongitudinal axis 30), and are aligned with one another along a planetransverse to the longitudinal axis 30. In other words, the slots 206are cut at approximately the same axial location along the length of theplug 16. The slots 206 have faces 208 that are parallel to one anotherand parallel to the longitudinal axis 30. The faces 208 are alsoparallel to the faces 188 and 166 of the first slots 164 and 186 in thefirst and second sections 160 and 176, respectively. A lower face 210 ofeach slot 206 is perpendicular to the face 208 and to the longitudinalaxis 30. An upper face 212 of each slot 206 is angled relative to theface 208 and to the longitudinal axis 30. The angle between the upperface 212 and the face 208 is obtuse. In other words, the upper face 212defines a chamfer that extends from the outer surface of the fourthsection 196 to the face 208.

A pair of second slots 214 is cut into the outer surface of the fourthsection 196 proximate a second (downstream) end 152 of the plug 16. Theslots 214 are on opposite sides of the fourth section 196 from oneanother (e.g., offset on either side of the longitudinal axis 30), andare aligned with one another along a plane transverse to thelongitudinal axis 30. In other words, the slots 214 are cut atapproximately the same axial location along the length of the plug 16.The slots 214 have faces 216 that are parallel to one another andparallel to the longitudinal axis 30. However, the slots 214 are notparallel to the first slots 206. The slots 214 are rotated 90 degreesabout the longitudinal axis 30 such that the faces 216 of the secondslots 214 are oriented perpendicular to the faces 208 of the first slots206 (e.g., planes passing through the first faces 208 and the secondfaces 216 are parallel to the longitudinal axis 30, and areperpendicular to one another). The faces 216 are also parallel to thefaces 178 and 198 of the first and second slots 174 and 194 in the firstand second sections 160 and 176, respectively. A lower face 218 of eachslot 214 is perpendicular to the face 216 and to the longitudinal axis30. An upper face 220 of each slot 214 is angled relative to the face216 and to the longitudinal axis 30. The angle between the upper face220 and the face 216 is obtuse. In other words, the upper face 220defines a chamfer that extends from the outer surface of the fourthsection 196 to the face 216.

FIG. 4B illustrates a view of a balancing chamber 230 that is internalto the plug 16. The balancing chamber 230 includes a fluid path thatextends from a first tap 232 in the second (downstream) end 152 of theplug 16 to a second tap 234 that is proximate the first (upstream) end150 of the plug 16. The balancing chamber 230 is energized via pressurethat enters at the first tap 234. In operation, as the fluid pressureexerts a force that acts on the plug 16 in the downstream direction (asindicated by arrow 233), the pressure at the first tap 232 exerts abalancing force that acts in the opposite direction (e.g., acting on theplug 16 in an upstream direction as indicated by arrow 235).

In the illustrated embodiment, the balancing chamber 230 includes afirst bore 236, a second bore 238, and a third bore 240. The first bore236 includes a cylindrical chamber that is coaxial with the longitudinalaxis 30 of the plug 16. The first bore 236 terminates at the first tap232 at one end, and into the second bore 238 at the other end. Incertain embodiments, the second bore 238 includes a cylindrical boreextending along the length of the plug 16, coaxial with the longitudinalaxis 30 and the first bore 236. However, the second bore 238 does notextend through the first (upstream) end 150 of the plug 16, butterminates internal to the plug 16. The second bore 238 has a diameter(e.g., 0.37 inches) that is less than the diameter of the first bore 236(e.g., 1.51 inches). The third bore 240 includes a cylindrical bore thatextends from the second bore 238 to the second tap 234 located on anexternal surface of the plug 16. In the illustrated embodiment, thesecond tap 234 is located on the top face 182 of the second set of slots174 in the second section 160 of the plug 16. The location of the secondtap 234 can be modified to provide a varying amount of balancing force.For example, the second tap 234 may be located further upstream ordownstream on the plug 16. The absence of direct contact seal to balancethe valve trim facilitates the use of a variety of seal materials inconstructing the control valve trim 14.

In the embodiments discussed above, the plug 16 includes a series ofsections 154, 160, 176, and 196 that increase in diameter from the first(upstream) end 150 to the second (downstream) end 152 of the plug 16.The sections 160, 176, and 196 of the plug 16 include multiple pairs ofslots 164, 174, 186, 194, 206, and 214 that are offset around thediameter of the plug 16. The slots 164, 174, 186, 194, 206, and 214 areconfigured to align with the annular recesses 62, 64, 66, 68, 70, and 71and protrusions 104, 106, 108, 110, 112, 114, and 116 of the liner 18 todirect flow in fluid path that includes a series of gentle turns.

FIGS. 5A-5C depict the fluid flow around the plug 16 and through thecontrol valve trim 14 in accordance with embodiments of the presenttechnique. Specifically, FIG. 5A illustrates an exemplary fluid flowpath 250 proximate the plug 16 if the plug 16 were disposed internal tothe liner 18. As illustrated, the fluid flow path 250 includes a seriesof gentle turns (e.g., turns having a bend angle of less than 90 degreesand/or less than approximately 45 degrees) as the fluid flows througheach of the six stages. The gentle turns may be attributed to acombination of the fluid being directed in varying directions along thelongitudinal axis 30 (e.g., an axial direction), flow that is normal tothe longitudinal axis (e.g., in a radial direction), and flow that iscircumferential (e.g., in a circular path along the circumference of theannular recesses 62, 64, 66, 68, 70, and 71, and the protrusions 104,106, 108, 110, 112, 114, and 116). The expanding area for the fluid toflow in each stage also contributes to reducing the bend angle or eachturn. In other words, fluid that is moving in an outward radialdirection may continue at least partially in the outward radialdirection as the fluid flow from a first stage (or chamber) having afirst diameter to a second stage (or chamber) having a diameter that isgreater than the first diameter.

FIG. 5B depicts the flow path 250 in a cross-sectioned view of the plug16 and the liner 18. FIG. 5C depicts two flow paths 250 in across-sectioned view of the plug 16 and the liner 18. Although in eachof the illustrations it may appear that the fluid flow path 250 includesturns that are greater than 45 degrees, the angle of the fluid flow pathmay not simultaneously reflect all three dimensions of the flow path250. For example, in FIG. 5C where the fluid path 250 includes bendsfrom each stage, there may also be an additional component of velocityacting transverse to the plane of the two dimensional figure.Accordingly, the control valve trim 14 may provide increased fluidcapacity, pressure throttling, and trash tolerance, with a reducedreliance on the temperature limitations that may be characteristic ofother balanced valves 12.

The specific embodiments of the control valve trim 14, including theplug 16 and the liner 18, depicted in FIGS. 2 through 5 are merelyexemplary and not intended to be limiting. For example, FIGS. 6 through9 present other exemplary embodiments of the plug 16 and liner 18, whichmay be used in the control valve trim 14. In particular, FIGS. 6A and 6Billustrate perspective views of another exemplary embodiment of the plug16 of the control valve trim 14. As illustrated, the plug 16 againincludes a series of generally cylindrical sections increasing indiameter from the first (upstream) end 150 to the second (downstream)end 152 of the plug 16. In particular, the embodiment illustrated inFIGS. 6A and 6B includes a first section 252 and a second section 254.However, in other embodiments, more than two sections may be used. Acollar section 256 may connect the first section 252 and the secondsection 254. As illustrated, the collar section 256 may generallyincrease in diameter along the longitudinal axis 30 from the firstsection 252 to the second section 254.

As opposed to the plug 16 described above with reference to FIGS. 1, 2,4, and 5, the exemplary embodiment of the plug 16 illustrated in FIGS.6A and 6B may not include a stem extending from the first end 150 of theplug 16. Rather, the present embodiment may include a stem 258 as acylindrical protrusion from the second end 152 of the plug 16. As such,the first end 150 of the plug 16 illustrated in FIGS. 6A and 6B mayinclude a generally conical surface from a cap end 260 of the plug 16 tothe first section 252, over which fluid may flow through the controlvalve trim 14. The stem 258 extending from the second end 152 of theplug 16 may be coupled to the actuator mechanism 28, as discussed abovewith respect to FIG. 1.

In addition to the second section 254 having a generally larger diameterthan the first section 252, each individual section may also generallyincrease slightly in diameter along the longitudinal axis 30 from anupstream portion to a downstream portion. For example, the first section252 may increase slightly (e.g., 10%) in diameter from the first end 150of the plug 16 to the collar section 256. However, just upstream of thecollar section 256, a small tail portion 260 of the first section 252may decrease in diameter. This decrease in diameter may, for instance,enable smoother transition of the fluid flow from the first section 252to the collar section 256. In addition, the second section 254 mayincrease slightly (e.g., 10%) in diameter from the collar section 256 ofthe plug 16 to the second end 152 of the plug 16. However, just upstreamof the second end 152, a small tail portion 262 of the second section254 may decrease in diameter. Again, this decrease in diameter may, forinstance, allow for smoother transition of the fluid flow from thesecond section 254.

The embodiments described above with respect to FIGS. 2 through 5depicted plugs 16 which include multiple slots on opposite sides ofsections of the plug 16. In contrast, the first section 252 of the plug16 illustrated in FIGS. 6A and 6B may, for instance, include threescoop-like depressions 264 (e.g., curved or concave depressions) withinthe generally cylindrical surface of the first section 252 of the plug16. As illustrated, the depressions 264 may be spaced equally around thecircumference of the first section 252 such that all three depressions264 are similarly shaped and the resulting three ridges 266 adjacent tothe depressions 264 are also similarly shaped. More specifically, eachof the three depressions 264 may be spaced 120 degrees from each otherabout the longitudinal axis 30. Although illustrated as threedepressions 264, the number of depressions 264 used in the first section252 of the plug 16 may vary.

Similarly, the second section 254 of the plug 16 illustrated in FIGS. 6Aand 6B may also include three scoop-like depressions 268 (e.g., curvedor concave depressions) within the generally cylindrical surface of thesecond section 254 of the plug 16. Again, as illustrated, thedepressions 268 may be spaced equally around the circumference of thesecond section 254 such that all three depressions 268 are similarlyshaped and the resulting three ridges 270 adjacent to the depressions268 are also similarly shaped. More specifically, each of the threedepressions 268 may be spaced 120 degrees from each other about thelongitudinal axis 30. Also, although illustrated as three depressions268, the number of depressions 268 used in the second section 254 of theplug 16 may vary.

The depressions 264 of the first section 252 and the depressions 268 ofthe second section 254 may be spaced in such a way that the depressions264 of the first section 252 generally line up with ridges 270 of thesecond section 254. In addition, the depressions 268 of the secondsection 254 may generally line up with ridges 266 of the first section252. For instance, as illustrated, the depressions 268 of the secondsection 254 may be rotated 60 degrees about the longitudinal axis 30from the depressions 264 of the first section 252. This alternatingarrangement of depressions and ridges between interconnected stages ofthe plug 16 may enable a tortuous fluid path between the stages.

FIGS. 7A and 7B illustrate a perspective view and a cross-sectioned viewof another exemplary embodiment of the liner 18, for use with the plug16 illustrated in FIGS. 6A and 6B. Again, the liner 18 includes a linerbody 80 having a first (upstream) end 82 and a second (downstream) end84. The first end 82 is configured to direct fluid into an interiorcavity 272 of the liner 18. The liner 18 again includes an externalsurface 88 that facilitates disposing the liner 18 into the fluid bore20 of the valve 12. In other words, as described above, the profile ofthe external surface 88 is similar to and/or conforms to the profile ofan internal surface of the fluid bore 20. When the liner 18 is disposedin the fluid bore 20, the interface between the liner 18 and the fluidbore 20 may effectively create a seal, thereby forcing fluid from thebore 20 into the channel 32 of the control valve trim 14, as illustratedin FIG. 1.

The liner 18 also includes a first section 274 and a second section 276.As described below with respect to FIG. 8, the plug 16 illustrated inFIGS. 6A and 6B and the liner 18 generally interact within the firstsection 274 of the liner 18. The second section 276 of the liner 18 isgenerally the section of the liner 18 through which the fluid may exitthe interior cavity 272 of the liner 18. Specifically, the secondsection 276 of the liner 18 may include multiple openings 278 throughwhich the fluid may exit the interior cavity 272 of the liner 18.Although depicted as including four openings 278, the second section 276of the liner 18 may include any suitable number of openings 278.

The first section 274 of the liner 18 may include multiple internalbored sections which may facilitate interaction with the plug 16illustrated in FIGS. 6A and 6B. As illustrated in FIG. 7B, the liner 18may include a first bore 280 and a second bore 282. In general, thediameter of the second bore 282 is greater than the diameter of thefirst bore 280. In addition, a smooth transition from the smallerdiameter of the first bore 280 to the larger diameter of the second bore282 may be accomplished using a transition bore 284. The transition bore284 may gradually increase in diameter from the smaller diameter of thefirst bore 280 to the larger diameter of the second bore 282.

The depressions 264 on the first section 252 of the plug 16 illustratedin FIGS. 6A and 6B may generally interact with the interior surface ofthe first bore 280. In addition, the depressions 268 on the secondsection 254 of the plug 16 illustrated in FIGS. 6A and 6B may generallyinteract with the interior surface of the second bore 282. Inparticular, FIG. 8 illustrates a cross-sectioned view of the controlvalve trim 14, incorporating the exemplary embodiments of the plug 16and liner 18 described in FIGS. 6 and 7. As illustrated, as fluid flowsthrough the interior cavity 272 of the liner 18, the fluid may firstflow through the first bore 280 section, across the first section 252 ofthe plug 16. In the particular alignment illustrated in FIG. 8, thefluid may, for instance, flow along the right side of the first bore280, through the space created by the depression 264 on the right sideof the first section 252 of the plug 16. Similarly, as fluid continuesto flow through the interior cavity 272 of the liner 18, the fluid maynext flow through the second bore 282 section, across the second section254 of the plug 16. In the particular alignment illustrated in FIG. 8,the fluid may, for instance, flow along the left side of the second bore282, through the space created by the depression 268 on the left side ofthe second section 254 of the plug 16.

Similar to the embodiments described above with respect to FIGS. 2through 5, the alternating arrangement of the depressions 264 of thefirst section 252 of the plug 16 and the depressions 268 of the secondsection 254 of the plug 16 may enable the control valve trim 14 todirect the flow of fluid through a series of gentle turns. For example,FIGS. 9A and 9B depict fluid flows around the plug 16 illustrated inFIGS. 6 and 8. Specifically, FIGS. 9A and 9B illustrate exemplary flowpaths 290 proximate the plug 16 if the plug 16 were disposed internal tothe liner 18 illustrated in FIGS. 7 and 8. As illustrated, the fluidflow paths 290 include a series of gentle turns (e.g., turns having abend angle of less than 90 degrees and/or less than approximately 45degrees) as the fluid flows through the two stages.

As described above, the gentle turns may be attributed to a combinationof the fluid being directed in varying directions along the longitudinalaxis 30, flow that is normal to the longitudinal axis 30, and flow thatis circumferential. The expanding area for the fluid to flow in eachstage also contributes to reducing the bend angle or each turn. In otherwords, fluid that is moving in an outward radial direction may continueat least partially in the outward radial direction as the fluid flowfrom a first stage having a first diameter to a second stage having adiameter that is greater than the first diameter.

FIG. 10 is a block diagram that depicts a fluid system 300 employing thecontrol valve trim 14 in accordance with embodiments of the presenttechnique. As discussed previously with regard to FIG. 1, the controlvalve trim 14 may be disposed in the flow bore 20 of the valve 12, andthe valve 12 may be disposed in a fluid stream of the fluid system 300.In the fluid system 300, the fluid may pass through the valve 12, enterthe control valve trim 14 via an inlet, as indicated by arrow 302, andexit the control valve trim 14 as indicated by arrow 304. After exitingthe control valve trim 14, the fluid may be directed to other flowpaths, valves 12, and or control valve trims 14 located integral to orexternal to the fluid system 300.

The fluid system 300 may include any variety of systems that employvalves and/or throttling devices to regulate the flow of fluids (e.g., aliquid and/or gaseous state, which may or may not include suspendedsolids). For example, the fluid system 300 may include a system employedin the oil and gas industry, the power production industry, chemicalplants, or other such applications. In oil and gas applications, thevalve 12 and control valve trim 14 may be employed in a mineralextraction system (such as an oil and gas wellhead or christmas tree),in piping applications (such as a subsea or surface oil and gasmanifold), a processing system (such as an oil and gas refinery), and soforth. In the power production industry, the control valve trim 14 maybe employed in power plants to route and regulate the fluid flow ofsteam as it passes to and from power turbines. In chemical plants, thecontrol valve trim 14 may be employed integral with certain processes orin line with various pipes to regulate the flow of liquids and gasesbetween production facilities and processes. These systems may includefluid flow capacity (Cv—the volume of water in US gallons per minutethat will flow through the coupling with a pressure drop of 1 psi) inexcess of 1000 Cv.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

The invention claimed is:
 1. A control valve system, comprising: a plugcomprising a series of generally cylindrical sections increasing indiameter along a longitudinal axis of the control valve system, whereineach generally cylindrical section of the generally cylindrical sectionscomprises a plurality of concave depressions formed in an outer radialsurface of the respective generally cylindrical section, wherein a firstplurality of concave depressions of a first generally cylindricalsection of the series of generally cylindrical sections iscircumferentially offset from a second plurality of concave depressionsof a second generally cylindrical section of the series of generallycylindrical sections, and wherein at least one generally cylindricalsection of the generally cylindrical sections comprises at least oneconcave depression of the respective plurality of concave depressionsthat extends an entire axial length of the outer radial surface of theat least one generally cylindrical section relative to the longitudinalaxis of the control valve system; and a liner comprising a plurality ofradial holes disposed at a downstream end of the liner, wherein eachradial hole of the plurality of radial holes extends from an externalsurface of the liner to an internal surface of the liner, and eachradial hole of the plurality of radial holes is completely axiallyoffset from the series of generally cylindrical sections of the plugrelative to the longitudinal axis of the control valve system; whereinthe liner comprises a series of bores along the longitudinal axis,wherein the series of bores increase in diameter from an inlet of theliner to an exit of the liner.
 2. The control valve system of claim 1,wherein the first generally cylindrical section slightly increases indiameter from a first upstream portion of the first generallycylindrical section to a first downstream portion of the first generallycylindrical section.
 3. The control valve system of claim 2, wherein thesecond generally cylindrical section slightly increases in diameter froma second upstream portion of the second generally cylindrical section toa second downstream portion of the second generally cylindrical section.4. The control valve system of claim 3, wherein the plug comprises acollar section extending from the first downstream portion of the firstgenerally cylindrical section to the second upstream portion of thesecond generally cylindrical section, wherein the collar sectionincreases in diameter from the first downstream portion of the firstgenerally cylindrical section to the second upstream portion of thesecond generally cylindrical section.
 5. The control valve system ofclaim 1, wherein the plug comprises a generally conical cap surface atan upstream end of the plug.
 6. The control valve system of claim 5,wherein the plug comprises a stem extending from a downstream end of theplug.
 7. The control valve system of claim 1, wherein the firstplurality of concave depressions is spaced equidistantly about acircumference of the first generally cylindrical section of the seriesof generally cylindrical sections, and the second plurality of concavedepressions is spaced equidistantly about a circumference of the secondgenerally cylindrical section of the series of generally cylindricalsections.
 8. A control valve trim, comprising: a plug, comprising: aplurality of sections arranged in series along a longitudinal axis ofthe plug, wherein each section of the plurality of sections comprises adiameter that is greater than the diameter of the preceding section; anda plurality of concave depressions formed in an outer radial surface ofeach section of the plurality of sections, wherein each concavedepression of the plurality of concave depressions extends onlypartially about a circumference of the respective section, and whereinat least one section of the plurality of sections comprises at least oneconcave depression of the respective plurality of concave depressionsthat extends an entire axial length of the outer radial surface of theat least one section relative to the longitudinal axis of the plug; anda liner, wherein the plug is disposed internal to the liner, and whereinthe liner comprises a plurality of radial holes disposed at a downstreamend of the liner, wherein the plurality of radial holes extends from anexternal surface of the liner to an internal surface of the liner, andeach radial hole of the plurality of radial holes is completely axiallyoffset from the plurality of sections of the plug relative to thelongitudinal axis of the plug; wherein the liner comprises a pluralityof internal bored sections arranged in series along a longitudinal lineraxis about an interior of the liner, wherein each internal bored sectionof the plurality of internal bored sections comprises a first diameterthat is greater than a second diameter of the preceding internal boredsection, and wherein each section of the plurality of sections of theplug corresponds to a respective internal bored section of the liner. 9.The control valve trim of claim 8, wherein a first plurality of concavedepressions of a first section of the plurality of sections iscircumferentially offset from a second plurality of concave depressionsof a second section of the plurality of sections.
 10. The control valvetrim of claim 8, wherein each section of the plug includes three concavedepressions, and wherein a first set of three concave depressions in afirst section of the plurality of sections is rotated 60 degrees from asecond set of three concave depressions in a second section of theplurality of sections.
 11. The control valve trim of claim 8, whereinthe plug comprises a generally conical cap surface at an upstream end ofthe plug.
 12. The control valve trim of claim 8, wherein the plugcomprises a stem extending from a downstream end of the plug.
 13. Thecontrol valve trim of claim 8, wherein each section of the plurality ofsections comprises a tail portion formed in the outer radial surface ofthe respective section, wherein the tail portion tapers radially inwardfrom an upstream end of the control valve trim to a downstream end ofthe control valve trim relative to the longitudinal axis of the plug.